Joint holding time and rate utility based access model for cognitive radio network

Spectrum handoff (HO) is one of the main issues in cognitive radio networks. Spectrum handoff occurs when the owner of the spectrum or the primary user (PU) reclaims a channel already used opportunistically by a secondary user (SU). In this case, the SU has to vacate this channel and select another free one. This process has a negative impact on the performance of SU transmission in terms of delay and link maintenance, specially because of the unpredictable PU behavior. In this paper, the problem of minimizing the secondary user (SU) handoff process because of primary user activity is underlined. A mixed Integer non Linear Programming formulation of the problem is detailed and a channel selection strategy is proposed. The main idea of this access model is to select channels maximizing the preference of the secondary user towards the holding time and the achievable throughput. The SU preference is expressed using a microeconomic concept of Sigmoid utility. The performance and the suitability of the proposed access model is investigated through numerical simulations.